There are many LED retrofit and replacement lamps in the market today. In particular, linear LED lamps are becoming more available by different manufacturers to replace fluorescent lamps using existing lampholders in fixtures. There are LED lamps that are powered by existing ballasts. There are LED lamps that are powered by direct line alternating current voltage mains power where the ballast and starter if present is bypassed or removed. There are LED lamps that are powered by a DC power supply or direct current voltage LED driver. Lastly, there are LED lamps that can be powered by electromagnetic induction. For each LED lamp and power source combination, a unique circuit is designed specifically to operate the LEDs with that particular power supply.
There becomes a need for one LED lamp with a circuit design that will work for multiple power sources. The one LED lamp will allow for reduced inventory and lower production costs. The use of voltage regulating devices along with other electrical components will allow the LED lamp to be used with ballast power, alternating current voltage or VAC mains power, direct current voltage or VDC power, and inductive transfer power.
Voltage regulating devices include the family of voltage regulators including but not limited to electromechanical regulators, DC voltage stabilizers, active regulators, linear series regulators, switching regulators, combination (hybrid) regulators, constant current regulators, DC-to-DC converter regulators, buck converter regulators, boost converter regulators, zener shunts, zener clamps, zener clippers, DC-to-AC converter regulators, inverters, etc.
The additional use of voltage reducing devices will allow the LED lamp to withstand high voltage surges from the ballast during startup, and voltage transients during normal operation of the LED lamp. These devices work with both AC and DC power. Several technologies are available to defend equipment against the damaging effects of power surges. These include devices which protect against excessive current, such as fuses and PTCs, and those that protect against excessive voltages, such as Sidactors, Tranzorbs, MOVs, glass discharge tubes, zener diodes, resistors, capacitors, inductors, varistors and spark gaps, just to name a few. No step-down transformers or capacitors in series with the power source will be used. This will allow the LED lamp device of the present invention to be used with the multiple power sources described.
The LED lamp device of the present invention can use different types of LEDs. High brightness LEDs are available in discrete radial lead lamps, or in surface mount SMD or SMT packages. Surface mount LEDs are semiconductor devices that have pins or leads that are soldered on the same side as the components. As a result there is no need for feed through holes where solder is applied on both sides of the circuit boards. Therefore, surface mount LEDs can be used on single sided boards and are mounted flat to the surface without angular offsets. They are usually smaller in package size, and the beam spreads are wider than discrete radial lead LED lamps.
OLEDs or organic light emitting diodes are an up and coming technology for illumination lamp devices. An organic light emitting diode (OLED), also light emitting polymer (LEP), and organic electro luminescence (OEL), is an LED whose emissive electroluminescent layer is composed of a film of organic compounds. The layer usually contains a polymer substance that allows suitable organic compounds to be deposited. They are deposited in rows and columns onto a flat carrier by a simple “printing” process. The resulting matrix of pixels can emit light. OLEDs can be used in light sources for general space illumination and large area light emitting elements. OLEDs typically emit less light per area than inorganic solid-state based LEDs that are usually designed for use as point-light sources.
An LED or light emitting diode is a special diode that emits light when DC power is applied. Each LED can be arranged in an anti-parallel connection with another diode or another LED as a single pair or as part of a pair of anti-parallel diode strings. Each anti-parallel serial string of at least one diode pair is in series with a current limiting device such as a resistor or a capacitor. The current limiting capacitor can be used for AC voltages, but will block DC power to the LEDs. Therefore, the resistor is a preferred device for the present invention, because it will allow both AC and DC voltages to pass to the series string of anti-parallel diode pairs.
An anti-parallel connection has at least two diodes connected to each other in opposing parallel relation, at least one or both such diodes are each an LED. The diode pairs are connected in parallel such that an anode of a first diode in the pair is electrically connected to the cathode of the other second diode in the pair, and the anode of the second diode is electrically connected to the cathode of the first diode in the pair. One of each pair of diodes is thus forward biased to produce light regardless of the instantaneous polarity of electrical current supplied to the diode pair by the power source. The anti-parallel diode pairs can also consist of at least two anti-parallel diode strings separated into two separate diode strings that can conduct in opposite electrical directions. Within each anti-parallel diode string pair, a same number of diodes are electrically connected with each number of diodes that can conduct in a different electrical direction. A current limiting resistor is connected to the anti-parallel diode string pair at one point and the value of the resistor is selected to reduce the input power to activate one of the two diode strings in the anti-parallel diode string pair one at a time. At least one or all diodes in each anti-parallel diode string pair is each an LED.
Besides using individual and discrete components in most implementation of the invention, the diodes in each pair will be normal single-die LEDs. Another aspect of the invention provides, however for a multi-die LED such that the diode pair comprises at least two LED dies mounted with reverse polarity within a single LED casing. It should be noted that “package” or “packaged” or “PCB” is defined herein as an integrated unit meant to be used as a discrete component in either of the manufacture, assembly, installation, or modification of an LED lighting device or system.
Such a package includes LEDs of desired characteristics in series with current limiting resistors sized relative to the specifications of the chosen opposing parallel diodes and with respect to a predetermined AC voltage and frequency. The Acriche Emitter type is a discrete AC LED and the Acriche PCB type is an AC LED package that is offered by Seoul Semiconductor as the world's first AC-driven semiconductor lighting sources.